They are in his kitchen. They are in his basement, on shelves of fluorescent-lit terrariums and tables coated with a thin layer of dirt. And they're in his backyard, on white plastic tables filled with plant pots, perched next to their more innocent garden kin - black-eyed Susans and tomatoes and cilantro.

"I like to tell people that growing carnivorous plants is a consuming hobby," he said with a smile.

MacDonald, 49, certainly doesn't look like a mad scientist in his blue polo, jean shorts and sneakers. By day, he does computer support at Pfizer. And as he describes his beloved plants, being a mad scientist seems less and less like a job requirement for cultivating the things.

They're not all toothy and exotic and Amazonian. There are more than 600 naturally occurring kinds in the world. They can grow on a windowsill or in a plastic bag. They're found on every continent except Antarctica - some are even native to Connecticut. In verdant bunches in and around his house, they're all green and vaguely rhubarb-colored, with purply veins spidering up through the leaves. Some have flowers, pale and sticky and fibrous; some have stalks a couple of feet high.

They have names like "Prunus lusitanica," "Nepenthes sanguinea" and "Pinguicula pirouette." They house matted clusters of insect carcasses, but that's okay - better there than buzzing over a half-full trash can or gnawing away at the vegetables.

"Aren't they gorgeous?" MacDonald said.

And you start to believe him.

MacDonald has always been a plant-lover, thanks in large part to his African violet-growing grandmother, who taught him to root a leaf in a jelly jar. It was just before high school when he stumbled on a book about carnivorous plants, but it wasn't until nine years ago that he began seriously growing them.

With the help of online research, he went all out.

The Internet and its readily available instructions on how to do just about anything have helped carnivorous plant-breeding grow in popularity, MacDonald says, allowing for something like the International Carnivorous Plant Society to exist, and flourish.

Founded in 1972, according to its website at www.carnivorousplants.org, it is an organization of horticulturists, conservationists, scientists and educators interested in sharing the knowledge and news of their favorite kind of plant.

They have a newsletter. They have a YouTube channel. And about every two years since 1997, they've held a conference for carnivorous plant enthusiasts. It's been held in France, Germany, Australia, Japan. Last year's was in the Netherlands, with some 120 participants and 8,500 exhibition visitors, the website says.

Conference 2012 will be hosted in Seekonk, Mass., this weekend by the New England Carnivorous Plant Society, of which MacDonald has been an active member for nine years - coinciding with the time he began his own cultivation. About 70 people usually attend their monthly meetings.

Regarding the inevitable "Little Shop of Horrors" jokes - the movie musical about a venus flytrap hungry for human flesh - the NECPS embraces it. They even played the soundtrack over speakers and had the movie playing in the background at their last show, he said.

As it turns out, there's a lot to learn. For instance, there are three types of carnivorous plants: active, like the famous flytrap; sticky, like the Mexican butterwort, with a slimy, bug-trapping surface; and passive, with "pitchers" of tubular leaves that hold digestive enzymes for their insect meals.

Carnivorous plants are biologically built to be survivors, sprouting in barren soil and absorbing mineral-less water. Ironically enough, that means the care even the most experienced gardener would assume they need might actually be toxic.

"The problem is that they need special soil and special water, because they developed in areas where they have very nutrient-poor soil and water," he said. "So if you try to water them with standard tap water, you're probably going to kill them."

Growing the plants isn't terribly labor-intensive. Most days, MacDonald just fills their water trays and trims the dead pitchers. In the spring he repots after a hibernation period in his garage. But mostly, he just enjoys watching them bloom.

He'll bring about 70 plants in all to the conference.

"Our mission is really to get these plants out in front of the public and share our love of them with people who haven't really had a chance to experience them," he said.

MacDonald insists that experiencing the wonder of carnivorous plants does not require a particular scientific aptitude.

"I've been growing plants long enough that I can spout Latin names and I kind of know what people are talking about," he said. "But I am doing it for the love of growing them, not for the fascination of the science behind it."